Adam Øigaard

Electrical spike activity in the human small intestine

An intraluminal probe with 10 pairs of bipolar electrodes was used for continuous recording of myoelectric activity along the entire small intestine during 24 hr in 2 normal fasting human subjects. Two types of regular migrating activity were observed: (1) Bands of a great number of spike potentials appearing at hourly intervals migrating through the entire small intestine. This activity, corresponds to phase III of the “interdigestive myoelectric complex” described in animal experiments. (2) Bursts of a few spike potentials appearing with minute intervals migrating only through the jejunum. This activity has not previously been demonstrated in man nor in intact animals, but corresponds to the “minute-rhythm” described fromin vitro experiments.

Variations in size of the normal kidney following intravenous administration of water-soluble contrast medium and urea

Abstract Variations in kidney area were measured on X-ray films following the injection of contrast medium and urea. A mean increase of 7·8 per cent following contrast-medium injection was demonstrated in hypertensive patients with normal renal arteries. In normotensive patients the mean increase was 4·8 per cent. Additional infusion of urea (washout urography) in the hypertensive group produced a further increase in renal area to an average maximum of 11·4 per cent. A rise in interstitial pressure associated with intrarenal vasodilatation is a possible explanation. The response has physiological and clinical implications.

A Dose-Reducing Fluoroscopy System: Dose Measurements and Clinical Evaluation

Abstract A system based on pulsed fluoroscopy and image storage on a video disc recorder was developed to reduce fluoroscopic x-ray dose. It can be applied to any radiologic examination requiring fluoroscopy. An MVR disc recorder was used in connection with a conventional x-ray unit. Separate dose measurements for fluoroscopy and film-exposure radiation were obtained during 50 examinations of the stomach. The results were compared to those in 50 conventional television fluoroscopy studies. Average 90% reduction in fluoroscopy dosage was obtained, using 1 forty-msec x-ray pulse/second. Stepwise changing of the fluoroscopic images permitted sufficient impression of gastric dynamics.

The relative significance of electrical spike potentials and intraluminal pressure waves as quantitative indicators of motility

The relative significance of electrical spike potentials and intraluminal pressure waves as quantitative indicators of motility was studied from registrations in the human small intestine. The time interval between spike potentials and corresponding pressure waves was inversely proportional to the magnitude of the pressure waves. Amplitude and duration of pressure waves were proportional to the degree of visible activity as observed by synchronized cinefluorography. Duration of spike potentials also correlated well with visible intestinal activity, whereas amplitude of spike potentials showed a great range in variation. Correlations between all possible combinations of the four parameters (1) amplitude of spike potentials, (2) duration of spike potentials, (3) amplitude of pressure waves, and (4) duration of pressure waves were calculated on a computer for 1,000 corresponding pairs of spike potentials and pressure waves.

Quantitative analysis of motility recordings in the human small intestine

Simultaneous records of intraluminal pressure and electrical-action potentials (spike potentials) in the human duodenum were analyzed quantitatively by means of a stepwise scale of increasing activity, considering the frequency of spike potentials in combination with the frequency, duration, and amplitude of pressure waves. The analysis of consecutive 50-second periods was set up in a chart which can also be prepared in the form of a punched card representing an ultrashort summary of the intestinal motor activity throughout the entire examination. The abovementioned quantitative classification was related to visible motor activity by means of synchronized cinefluorography. The system described for quantitative motor analysis in the gastrointestinal tract is fast and easy to practice and may be useful for clinical motility studies.

Variations in renal size in the diagnosis of renovascular hypertension.

Abstract Following the injection of water-soluble contrast medium and urea an increase in area of the renal shadow of less than 5 per cent was demonstrated on the affected side in 14 cases of hypertension due to renal artery stenosis (verified by operation and post-operative follow-up). On the contra-lateral side an increase of 7–20 per cent was observed in all cases. In 20 patients with hypertension and renal artery stenosis, but no surgical intervention, the same phenomenon was observed in six cases. In these patients other diagnostic criteria were also indicative of reno-vascular hypertension. It is concluded that the increase in renal size which is normally seen following the injection of water-soluble contrast medium and certain drugs is impaired in cases of significant renal artery stenosis. The underlying mechanism (also discussed in a previous paper) may in itself be responsible for the hypertension. If this be the case, measurements of variations in renal size during washout urograms would be ver...

The narrow vestibular aquaeduct. An unspecific radiological sign

SummaryTomography of the vestibular aquaeduct was carried out in patients with Ménières disease, patients with chronic otitis and in patients without ear disorders. Visualization of the vestibular aquaeduct was evaluated blindly. The descending part of the aquaeduct was clearly visible in 95% of patients without ear disease. In the other groups, including contralateral non-affected ears in Ménière patients, the aquaeduct was clearly visible in only about 50%. The incidence of narrow or invisible aquaeducts in Ménière patients and in patients with chronic otitis was essentially the same. This radiologic finding seems to be an unspecific sign, present possibly in a variety of ear disorders.

Electrical spike potentials of the small bowel: a comparative study of recordings obtained from muscular implanted and intraluminal suction electrodes.

Electrical spike potentials from the canine duodenum have been recorded from intramuscular implanted and intraluminal suction electrodes. There was a significantly greater amplitude of the spike potentials recorded from implanted electrodes, otherwise the potentials were identical in number, duration and time of onset. Thus spike potentials recorded from suction electrodes, as used in clinical motility studies, accurately represent the event within the muscular layer.

Renal distension in response to water-soluble contrast medium and various diuretics.

Measurement of the increase in area of the renal silhouette, as it appears on radiographs following the administration of water-soluble contrast medium and certain diuretics, seems to be useful in the diagnosis of renovascular hypertension. In order to assess the optimal technique for such measurements, washout urography was performed in 32 hypertensive patients in two consecutive examinations so that the distensive effect of etacrynic acid, furosemide and hypertonic mannitol, respectively, were compared with that of urea in the same patients. In spite of their stronger diuretic effect, none of the above-mentioned diuretics caused a greater renal distension than urea, the maximum increase in area of the renal silhouette being about 7 to 20%, average about 11%. Since urea is probably the best siuted diuretic for the washout test, it seems to be the drug of choice for these diagnostic procedures.

Electrode problems in the recording of action potentials in the human small intestine

Spike potentials in the human duodenum were recorded simultaneously with several pairs of bipolar electrodes differing in size, shape, interelectrode distance and orientation. An increase in amplitude was observed with increasing interelectrode distance (1–5 mm), but otherwise the potentials did not differ significantly. Spike potentials recorded with platinum electrodes did not differ from those recorded with copper electrodes of identical size and shape.